Enable adding multiline GPG key.

linux/system/repo.sls

@@ -85,7 +85,8 @@ linux_repo_{{ name }}_pin:
 
 linux_repo_{{ name }}_key:
   cmd.wait:
-    - name: "echo '{{ repo.key }}' | apt-key add -"
+    - name: |
+        echo '{{ repo.key|indent(8, false) }}' | apt-key add -
     - watch:
       - file: default_repo_list
 
@@ -141,8 +142,10 @@ linux_repo_{{ name }}:
 
 linux_repo_{{ name }}_key:
   cmd.run:
-    - name: "echo '{{ repo.key }}' | apt-key add -"
-    - unless: "apt-key finger --with-colons | grep -qF $(echo '{{ repo.key }} | gpg --with-fingerprint --with-colons | grep -E '^fpr')"
+    - name: |
+        echo '{{ repo.key|indent(8, false) }}' | apt-key add -
+    - unless: |
+        apt-key finger --with-colons | grep -qF $(echo '{{ repo.key|indent(8, false) }}' | gpg --with-fingerprint --with-colons | grep -E '^fpr')
     - require_in:
       - pkgrepo: linux_repo_{{ name }}